Video applications are quickly emerging as an essential component of effective Public Safety communications. Accordingly, minimum quality standards for Public Safety video systems are beginning to emerge. For example, the Video Quality in Public Safety (VQiPS) Working Group was created to develop technical performance specifications and standards for the use of video in Public Safety applications.
Among other metrics specified, the video quality standards will indicate a minimum pixel density, meaning a minimum number of pixels over an area spanning an object of interest (e.g., a person, a car, etc.) in a video frame to complete a specified mission or use of the video (e.g., Positive Identification (ID)). A minimum pixel density metric may, for instance, serve as a standard as to whether or not certain video content is acceptable evidence in a court of law. Simply specifying an encoded frame resolution (e.g., 640×480) is not sufficient since, depending on the optical field of vision (FoV) of the camera used to generate the video frame, the object of interest may or may not occupy a sufficient number of pixels to complete a specified mission. For example, although 320×240 is a seemingly “low” encoded resolution, it may be sufficient if the field of vision of the camera is such that the object of interest occupies all 320×240 captured pixels. Conversely, although 1280×720 is a seemingly “high” resolution, it may be insufficient for a given mission if the object of interest occupies only 160×120 pixels of the overall frame.
In addition to the minimum pixel density, other parameters are important to consider when using video for Public Safety applications. For example, for a given mission, it is often important to maintain a maximum field of vision in order to maximize situational awareness for Public Safety officers monitoring the video. Moreover, many times the video captured for the mission is sent to viewers over a wireless network, wherein the current throughput of the network impacts the quality of the transmitted video. However, there currently exists no mechanism for taking into consideration all of these factors in capturing video for use in certain applications, such as Public Safety applications.
Accordingly, there is a need for a method and apparatus for maintaining a minimum pixel density across an object of interest within video transmitted over a wireless network.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments. In addition, the description and drawings do not necessarily require the order illustrated. It will be further appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Thus, it will be appreciated that for simplicity and clarity of illustration, common and well-understood elements that are useful or necessary in a commercially feasible embodiment may not be depicted in order to facilitate a less obstructed view of these various embodiments.